1) Field of the Invention
The present invention relates generally to cotton harvesters and, more specifically, to cotton harvesters able to harvest a large number of rows in a single pass.
2) Related Art
Cotton harvesters, such as the commercially available John Deere 7445 Cotton Stripper having brush type row units, can harvest up to four widely spaced rows of cotton or six narrowly spaced rows of cotton. A cross auger supported from the front of the frame of the harvester supports stripper row units in a variety of configurations to match numerous row spacings. At the center of the cross auger, cotton is sucked upwardly in a separation chamber by a vacuum created by a fan blowing air into nozzle above the chamber. Cotton is propelled through a single duct which extends upwardly behind the harvester cab and forwardly of a cleaner or bur extractor mounted on the harvester frame. Such a cleaner with bypass grate and door control structure is shown, for example, in U.S. Pat. No. 4,606,177.
Increasing the capacity of a harvester such as the 7445 Stripper beyond six rows of narrowly spaced cotton presents numerous problems. Moving a large volume of stripped cotton and plant material heavily taxes the conveying system so that maintaining a reliable flow through the auger, separation chamber and duct is a continuing source of difficulty. A large volume of air is required to move the material through the separation chamber and upwardly toward the cleaner, and efficiency of the air system is reduced by changes in direction of air flow between the fan outlet and the nozzle on the duct. Although improvements in cleaner design have resulted in increased cleaning capacity, the cleaner often is unable to handle the volume of material received from more than six row units operating in high yield cotton unless the harvester ground speed is reduced. If the cleaner or bur extractor is widened for increased capacity, larger and heavier cleaner drums and shafts are required which add to the weight and cost of the machine and raise the center of gravity of the harvester. Providing space on existing harvesters for the equipment necessary for adequate conveying and cleaning capacity for more than six rows of cotton, providing accessible drive for such equipment, and providing sufficient vertical range necessary for ground clearance and good ground-following ability with a wide cross auger have also been problems.